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ascitiesburn69
04-18-2009, 10:06 PM
Ok I'm having trouble figuring out the Vent length given to me in Winisd or BBP etc.
In this Picture http://img4.imageshack.us/img4/2589/p1000515k.th.jpg (http://img4.imageshack.us/my.php?image=p1000515k.jpg). Is the Vent length the length of the line that says Port length +.75 for thickness of wood. or is it port length plus 1/2 width of the port+ .75 for thickness of wood?
And in this pic: http://img21.imageshack.us/img21/453/p1000515f.th.jpg (http://img21.imageshack.us/my.php?image=p1000515f.jpg) Is the port length the length of the Line that says Port length plus half of the port width plus the length of the left side Plus length of Right side? or is it just either the left or right side+ the line that says port length?
Sorry about horrible drawing :rolleyes: and if i confused anyone just LMK and i'll attempt to clarify

PSturmer
04-18-2009, 11:14 PM
port length is the middle of the port but it should be longer than what your calculating it to be. read about end correction here:

http://mobile.jlaudio.com/support_pages.php?page_id=165

ascitiesburn69
04-19-2009, 01:37 AM
Thanks alot for that site. Very informative. Anyone else wanna chime in about ports that do not use a wall of the enclosure as a side?

mattxc
04-19-2009, 01:53 AM
no, but as cities burn = amazing

ascitiesburn69
04-19-2009, 03:15 AM
Lol yea they really are. I remember seeing them when they first started out. and then again with underoath at the new orleans House of Blues. **** that was a good concert.
But seriously anyone wanna help me out with this?

ascitiesburn69
04-19-2009, 12:12 PM
Bump

dman4486
04-19-2009, 12:15 PM
jeebus noobx

http://www.caraudio.com/forum/showthread.php?t=137804

look at the red lines and numbers...

ascitiesburn69
04-19-2009, 12:20 PM
I looked at that but some of the pictures have the port length line extending half the port width past the port and some dont....

dman4486
04-19-2009, 12:24 PM
I looked at that but some of the pictures have the port length line extending half the port width past the port and some dont....

it is an end correction factor, and will not make a noticeable difference

ascitiesburn69
04-19-2009, 12:27 PM
If i have a 5.5" wide port then thats 2.65" extra inches which could drop my tuning 1-2hz easily.

dman4486
04-19-2009, 12:27 PM
If i have a 5.5" wide port then thats 2.65" extra inches which could drop my tuning 1-2hz easily.

end correction is not .5 port width

dman4486
04-19-2009, 12:29 PM
http://www.ajdesigner.com/phpsubwoofervented/port_length_equation_k.php

ascitiesburn69
04-19-2009, 12:31 PM
Nice site thanks for that.

ascitiesburn69
04-19-2009, 04:53 PM
when using a port length calculator do I put the internal volume before the port displacement or with the port displacement. For instance if I have a 5.8 cuft box before port displacements and the port I am going to use takes up .72 cuft, then when using a port length calculator do I use 5.8 cuft or 5.1 cuft ?

dman4486
04-19-2009, 08:30 PM
when using a port length calculator do I put the internal volume before the port displacement or with the port displacement. For instance if I have a 5.8 cuft box before port displacements and the port I am going to use takes up .72 cuft, then when using a port length calculator do I use 5.8 cuft or 5.1 cuft ?

I use after sub and port displacement because then it will be the most accurate for the final product.

ascitiesburn69
04-20-2009, 12:20 AM
ok Thanks alot dman you've been a great help to me. and yea i figured that because DJ from audioque generously hooked me up with a design and I was just curious how to make one for myself because my friends all come to me for audio hookups....So does 5.84net before any displacements with a 13.5 high and 5.3wide and 19"deep port in the middle of two SDC's look good for an approximately 38hz tuning?